BS EN 1838 : 2013 - Lighting Applications - Emergency Lighting

All safety signs and arrow signs required during emergency escape shall meet the requirements of ISO 3864-1, ISO 3864-4 (photometric) and EN ISO 7010 (design).

All signs and notices will need illumination to ensure they are clearly visible and legible. These can be illuminated with internal and external illumination. It’s important that the safety colour green stays green and the contrast colour white stays white (colour boundaries specified in ISO 3864).

Safety signs include escape route direction signs, emergency exit signs and other safety signs deemed by risk assessment.

Safety signs shall be in accordance with ISO 3864-1, ISO 3864-4 (photometric) and EN ISO 7010 (design).

Luminance of safety signs

The luminance of any area of safety colour of the sign shall be at least 2 cd/m2.

The ratio of the maximum to the minimum luminance within either white or the safety colour shall be not greater than 10:1.

The safety colour and contrast colour shall conform to the requirements of ISO 3864  and ISO 3864.

The minimum duration of illumination of the safety signs shall be 1 h.
Safety signs shall be illuminated to at least 50 % of the required luminance within 5 s and 100% required luminance within 60 s.

Viewing distance

As  an  internally  illuminated  sign  is  visible  at  greater  distance  than  an  externally  illuminated  sign  of  the same size the maximum viewing distance shall be determined by use of the following formula:

L= Z x H

where:

L is  the distance of observation
H is the height of the sign
Z is  the  factor  of  distance  

(Z is a constant: 100 for externally illuminated signs; 200 for internally illuminated signs)

* The dimensional units of H and Z need to be the same.